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ip_gre: Add support to collect tunnel metadata.
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Following patch create new tunnel flag which enable
tunnel metadata collection on given device.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pravin B Shelar authored and David S. Miller committed Aug 10, 2015
1 parent a9020fd commit 2e15ea3
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Showing 6 changed files with 216 additions and 28 deletions.
7 changes: 6 additions & 1 deletion include/net/ip_tunnels.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,8 @@ struct ip_tunnel_dst {
__be32 saddr;
};

struct metadata_dst;

struct ip_tunnel {
struct ip_tunnel __rcu *next;
struct hlist_node hash_node;
Expand Down Expand Up @@ -115,6 +117,7 @@ struct ip_tunnel {
unsigned int prl_count; /* # of entries in PRL */
int ip_tnl_net_id;
struct gro_cells gro_cells;
bool collect_md;
};

#define TUNNEL_CSUM __cpu_to_be16(0x01)
Expand Down Expand Up @@ -149,6 +152,7 @@ struct tnl_ptk_info {
struct ip_tunnel_net {
struct net_device *fb_tunnel_dev;
struct hlist_head tunnels[IP_TNL_HASH_SIZE];
struct ip_tunnel __rcu *collect_md_tun;
};

struct ip_tunnel_encap_ops {
Expand Down Expand Up @@ -235,7 +239,8 @@ struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
__be32 key);

int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
const struct tnl_ptk_info *tpi, bool log_ecn_error);
const struct tnl_ptk_info *tpi, struct metadata_dst *tun_dst,
bool log_ecn_error);
int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
struct ip_tunnel_parm *p);
int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
Expand Down
1 change: 1 addition & 0 deletions include/uapi/linux/if_tunnel.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -112,6 +112,7 @@ enum {
IFLA_GRE_ENCAP_FLAGS,
IFLA_GRE_ENCAP_SPORT,
IFLA_GRE_ENCAP_DPORT,
IFLA_GRE_COLLECT_METADATA,
__IFLA_GRE_MAX,
};

Expand Down
195 changes: 179 additions & 16 deletions net/ipv4/ip_gre.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
#include <linux/udp.h>
#include <linux/if_arp.h>
#include <linux/mroute.h>
#include <linux/if_vlan.h>
#include <linux/init.h>
#include <linux/in6.h>
#include <linux/inetdevice.h>
Expand All @@ -47,6 +48,7 @@
#include <net/netns/generic.h>
#include <net/rtnetlink.h>
#include <net/gre.h>
#include <net/dst_metadata.h>

#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
Expand Down Expand Up @@ -200,9 +202,29 @@ static int ipgre_err(struct sk_buff *skb, u32 info,
return PACKET_RCVD;
}

static __be64 key_to_tunnel_id(__be32 key)
{
#ifdef __BIG_ENDIAN
return (__force __be64)((__force u32)key);
#else
return (__force __be64)((__force u64)key << 32);
#endif
}

/* Returns the least-significant 32 bits of a __be64. */
static __be32 tunnel_id_to_key(__be64 x)
{
#ifdef __BIG_ENDIAN
return (__force __be32)x;
#else
return (__force __be32)((__force u64)x >> 32);
#endif
}

static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)
{
struct net *net = dev_net(skb->dev);
struct metadata_dst *tun_dst = NULL;
struct ip_tunnel_net *itn;
const struct iphdr *iph;
struct ip_tunnel *tunnel;
Expand All @@ -218,40 +240,162 @@ static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi)

if (tunnel) {
skb_pop_mac_header(skb);
ip_tunnel_rcv(tunnel, skb, tpi, log_ecn_error);
if (tunnel->collect_md) {
struct ip_tunnel_info *info;

tun_dst = metadata_dst_alloc(0, GFP_ATOMIC);
if (!tun_dst)
return PACKET_REJECT;

info = &tun_dst->u.tun_info;
info->key.ipv4_src = iph->saddr;
info->key.ipv4_dst = iph->daddr;
info->key.ipv4_tos = iph->tos;
info->key.ipv4_ttl = iph->ttl;

info->mode = IP_TUNNEL_INFO_RX;
info->key.tun_flags = tpi->flags &
(TUNNEL_CSUM | TUNNEL_KEY);
info->key.tun_id = key_to_tunnel_id(tpi->key);

info->key.tp_src = 0;
info->key.tp_dst = 0;
}

ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
return PACKET_RCVD;
}
return PACKET_REJECT;
}

static void build_header(struct sk_buff *skb, int hdr_len, __be16 flags,
__be16 proto, __be32 key, __be32 seq)
{
struct gre_base_hdr *greh;

skb_push(skb, hdr_len);

skb_reset_transport_header(skb);
greh = (struct gre_base_hdr *)skb->data;
greh->flags = tnl_flags_to_gre_flags(flags);
greh->protocol = proto;

if (flags & (TUNNEL_KEY | TUNNEL_CSUM | TUNNEL_SEQ)) {
__be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4);

if (flags & TUNNEL_SEQ) {
*ptr = seq;
ptr--;
}
if (flags & TUNNEL_KEY) {
*ptr = key;
ptr--;
}
if (flags & TUNNEL_CSUM &&
!(skb_shinfo(skb)->gso_type &
(SKB_GSO_GRE | SKB_GSO_GRE_CSUM))) {
*ptr = 0;
*(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0,
skb->len, 0));
}
}
}

static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
const struct iphdr *tnl_params,
__be16 proto)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
struct tnl_ptk_info tpi;

tpi.flags = tunnel->parms.o_flags;
tpi.proto = proto;
tpi.key = tunnel->parms.o_key;
if (tunnel->parms.o_flags & TUNNEL_SEQ)
tunnel->o_seqno++;
tpi.seq = htonl(tunnel->o_seqno);

/* Push GRE header. */
gre_build_header(skb, &tpi, tunnel->tun_hlen);

skb_set_inner_protocol(skb, tpi.proto);
build_header(skb, tunnel->tun_hlen, tunnel->parms.o_flags,
proto, tunnel->parms.o_key, htonl(tunnel->o_seqno));

skb_set_inner_protocol(skb, proto);
ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
}

static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ip_tunnel_info *tun_info;
struct net *net = dev_net(dev);
const struct ip_tunnel_key *key;
struct flowi4 fl;
struct rtable *rt;
int min_headroom;
int tunnel_hlen;
__be16 df, flags;
int err;

tun_info = skb_tunnel_info(skb, AF_INET);
if (unlikely(!tun_info || tun_info->mode != IP_TUNNEL_INFO_TX))
goto err_free_skb;

key = &tun_info->key;
memset(&fl, 0, sizeof(fl));
fl.daddr = key->ipv4_dst;
fl.saddr = key->ipv4_src;
fl.flowi4_tos = RT_TOS(key->ipv4_tos);
fl.flowi4_mark = skb->mark;
fl.flowi4_proto = IPPROTO_GRE;

rt = ip_route_output_key(net, &fl);
if (IS_ERR(rt))
goto err_free_skb;

tunnel_hlen = ip_gre_calc_hlen(key->tun_flags);

min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
+ tunnel_hlen + sizeof(struct iphdr);
if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
int head_delta = SKB_DATA_ALIGN(min_headroom -
skb_headroom(skb) +
16);
err = pskb_expand_head(skb, max_t(int, head_delta, 0),
0, GFP_ATOMIC);
if (unlikely(err))
goto err_free_rt;
}

/* Push Tunnel header. */
skb = gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM));
if (IS_ERR(skb)) {
skb = NULL;
goto err_free_rt;
}

flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
build_header(skb, tunnel_hlen, flags, htons(ETH_P_TEB),
tunnel_id_to_key(tun_info->key.tun_id), 0);

df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
err = iptunnel_xmit(skb->sk, rt, skb, fl.saddr,
key->ipv4_dst, IPPROTO_GRE,
key->ipv4_tos, key->ipv4_ttl, df, false);
iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
return;

err_free_rt:
ip_rt_put(rt);
err_free_skb:
kfree_skb(skb);
dev->stats.tx_dropped++;
}

static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct ip_tunnel *tunnel = netdev_priv(dev);
const struct iphdr *tnl_params;

if (tunnel->collect_md) {
gre_fb_xmit(skb, dev);
return NETDEV_TX_OK;
}

if (dev->header_ops) {
/* Need space for new headers */
if (skb_cow_head(skb, dev->needed_headroom -
Expand All @@ -277,7 +421,6 @@ static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
goto out;

__gre_xmit(skb, dev, tnl_params, skb->protocol);

return NETDEV_TX_OK;

free_skb:
Expand All @@ -292,6 +435,11 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
{
struct ip_tunnel *tunnel = netdev_priv(dev);

if (tunnel->collect_md) {
gre_fb_xmit(skb, dev);
return NETDEV_TX_OK;
}

skb = gre_handle_offloads(skb, !!(tunnel->parms.o_flags&TUNNEL_CSUM));
if (IS_ERR(skb))
goto out;
Expand All @@ -300,7 +448,6 @@ static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
goto free_skb;

__gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB));

return NETDEV_TX_OK;

free_skb:
Expand Down Expand Up @@ -596,8 +743,10 @@ static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
return ipgre_tunnel_validate(tb, data);
}

static void ipgre_netlink_parms(struct nlattr *data[], struct nlattr *tb[],
struct ip_tunnel_parm *parms)
static void ipgre_netlink_parms(struct net_device *dev,
struct nlattr *data[],
struct nlattr *tb[],
struct ip_tunnel_parm *parms)
{
memset(parms, 0, sizeof(*parms));

Expand Down Expand Up @@ -635,6 +784,12 @@ static void ipgre_netlink_parms(struct nlattr *data[], struct nlattr *tb[],

if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC]))
parms->iph.frag_off = htons(IP_DF);

if (data[IFLA_GRE_COLLECT_METADATA]) {
struct ip_tunnel *t = netdev_priv(dev);

t->collect_md = true;
}
}

/* This function returns true when ENCAP attributes are present in the nl msg */
Expand Down Expand Up @@ -712,7 +867,7 @@ static int ipgre_newlink(struct net *src_net, struct net_device *dev,
return err;
}

ipgre_netlink_parms(data, tb, &p);
ipgre_netlink_parms(dev, data, tb, &p);
return ip_tunnel_newlink(dev, tb, &p);
}

Expand All @@ -730,7 +885,7 @@ static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
return err;
}

ipgre_netlink_parms(data, tb, &p);
ipgre_netlink_parms(dev, data, tb, &p);
return ip_tunnel_changelink(dev, tb, &p);
}

Expand Down Expand Up @@ -765,6 +920,8 @@ static size_t ipgre_get_size(const struct net_device *dev)
nla_total_size(2) +
/* IFLA_GRE_ENCAP_DPORT */
nla_total_size(2) +
/* IFLA_GRE_COLLECT_METADATA */
nla_total_size(0) +
0;
}

Expand Down Expand Up @@ -796,6 +953,11 @@ static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
t->encap.flags))
goto nla_put_failure;

if (t->collect_md) {
if (nla_put_flag(skb, IFLA_GRE_COLLECT_METADATA))
goto nla_put_failure;
}

return 0;

nla_put_failure:
Expand All @@ -817,6 +979,7 @@ static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
[IFLA_GRE_ENCAP_FLAGS] = { .type = NLA_U16 },
[IFLA_GRE_ENCAP_SPORT] = { .type = NLA_U16 },
[IFLA_GRE_ENCAP_DPORT] = { .type = NLA_U16 },
[IFLA_GRE_COLLECT_METADATA] = { .type = NLA_FLAG },
};

static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
Expand Down Expand Up @@ -851,7 +1014,7 @@ static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {

static int __net_init ipgre_tap_init_net(struct net *net)
{
return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, NULL);
return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0");
}

static void __net_exit ipgre_tap_exit_net(struct net *net)
Expand Down
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